Insecticides and parasiticides

Abstract

The present invention relates to novel derivatives of formula I that can be derived from milbemycins, to their preparation and their use for controlling pests, and also to pesticides that contain at least one of these compounds as active ingredient. The novel compounds have the general formula I ##STR1## in which X is one of the groups --CH(OR 1 )--, --C(O)-- or --C(═N--OR)--; R 1 is hydrogen or an OH-protecting group; R is hydrogen, an OH-protecting group, or an alkyl or cycloalkyl group; R 2 is methyl, ethyl, isopropyl or sec.-butyl; and Ph is a phenyl ring that is substituted by R a , R b , R c and R d , wherein each of R a , R b , R c and R d , independently of the others, is hydrogen, C 1 -C 10 alkyl, C 2 -C 10 alkoxyalkyl, C 2 -C 10 alkenyl, C 1 -C 10 alkoxy, C 2 -C 10 alkoxyalkoxy, or a phenyl or phenoxy radical that is unsubstituted or is substituted by at least one substituent from the group C 1 -C 3 alkyl and C 1 -C 3 alkoxy.

What is claimed is: 
     
       1. A process for the preparation of compounds of formula I ##STR12## in which X is one of the groups --CH(OR 1 )--, or --C(═O)--or --C(═N--OR)--; R 1  is hydrogen, or an OH-protecting group;   R is hydrogen, an OH-protecting group, an alkyl group or a cycloakyl group;   R 2  methyl, ethyl, isopropyl or sec.-butyl; and   Ph is a phenyl ring that is substituted by R a , R b , R c  and R d , wherein each of R a , R b , R c  and R d , independently of the others, is hydrogen, C 1  -C 10  alkyl, C 2  -C 10  alkoxyalkyl, C 2  -C 10  alkenyl, C 1  -C 10  alkoxy, C 2  -C 10  alkoxyalkoxy, or a phenyl or phenoxy radical that is unsubstituted or is substituted by at least one substituent from the group C 1  -C 3  alkyl and C 1  -C 3  alkoxy;   which process comprises the step of reacting a compound of formula II ##STR13## wherein G is one of the groups a or b ##STR14## and E is chlorine, bromine or iodine; with a diaryl zinc compound of formula III   Ph--Zn--Ph                                                 (III),        in the presence of a transition metal salt selected from the group consisting of phosphines and amines of Fe, Ru, Os, Co, Rh, Ir, Ni, Pd and Pt substituted by organic residues, and, if desired, when R 1  is an OH-protecting group, removing that protecting group by hydrolysis, and in order to obtain compounds of formula I wherein X is C═O, treating compounds of formula I wherein X is --CH(OH)--with a reagent suitable for the purpose of oxidation or with a ketone in the presence of an aluminium alcoholate; and in order to obtain compounds of formula I wherein X is C(═NOR), reacting compounds of formula I wherein X is C═O with hydroxylamine or a salt thereof and, if desired, subsequently introducing the substituent R, or carrying out the reaction with a compound of formula NH 2  --OR or with a salt thereof wherein R in each case has the meanings given for formula I with the exception of hydrogen.   
     
     
       2. A process according to claim 1, which comprises carrying out the reaction in the presence of a transition metal salt that contains, as the metal component, Co, Ni or Pd. 
     
     
       3. A process according to claim 1, which comprises using as the transition metal salt NiCl 2 , CoCl 2 ,[(phenyl) 3  P] 2  NiCl 2 , [(phenyl) 3  P] 2  PdCl 2 , [(phenyl) 2  PCH 2  ] 2  NiCl 2 , [(phenyl) 2  PCH 2  CoBr 2 , [(phenyl) 2  PCH 2  CH 2  CH 2  P-(phenyl) 2  ]NiCl 2 , [(phenyl) 2  PCH 2  CH 2  ] 2  NiCl 2  or [(cyclohexyl) 3  P] 2  NiCl 2 .